Electron-discharge device of the magnetron type



March 28, 1950 w. c. BROWN 2,502,405

ELECTRON DISCHARGE DEVICE OF THE MAGNETRON TYPE Fifed Dec. 20, 1948 2 Sheefs-Sheet 1 33 2 3I Z r L 4 L 5 /NVENTOI? WILLIAM C. BROWN ATTORNEY March 28, 1950 w. 0. BROWN 0 ELECTRON DISCHARGE DEVICE OF THE MAGNETRON TYPE Filed Dec. 20, 1948 2 Sheets-Sheet 2 INVENTOI? WILLIAM C, BROWN ATTORNEY Patented Mar. 28, 1950 ELECTRON-DISCHARGE DEVICE OF THE MAGNETRON TYPE William C. Brown, Lincoln, Mass, assignor to Raytheon Manufacturing Company, Newton, Mass, a corporation of Delaware Application December 20, 1948, Serial No. 66,250

9 Claims.

This invention relates to electron-discharge devices, and more particularly to electron-discharge devices of the magnetron type.

It has heretofore been diificult to build a magnetron capable of delivering appreciable power under continuous-Wave operating conditions unless the tube was of considerable size and weight. Furthermore, the structure of such a tube was rather complicated and the tube, therefore, was difficult and expensive to make.

Hence, it is one of the objects of the present invention to avoid the above difiiculties by providing a magnetron which, while being of relatively small dimensions, is capable of generating appreciable radio-frequency power under continuous-wave operating conditions.

It is a further object of the present invention to provide a magnetron which accomplishes the foregoing object in a simple and economical manner.

In the accompanying Specification there shall be described, and in the annexed drawings shown, an illustrative embodiment of the electron-discharge device of the present invention. It is, however, to be clearly understood that the present invention is not to be limitedto the details herein shown and described for purposes of i1- lustration only, inasmuch as changes therein may be made without the exercise of invention, and within the true spirit and scope of the claims hereto appended.

In said drawings,

Fig. 1 is a. longitudinal sectional view taken substantially through the center of a magnetron made in accordance with the principles of the present invention;

Fig. 2 is a transverse sectional view taken along line 22 of Fig. 1; and

Fig. 3 is a similar view taken along line 3-3 of Fig. 1.

Referring now more in detail to the aforesaid illustrative embodiment of the present invention, with particular reference to the drawings illustrating the same, the numeral It! generally designates an electron-discharge device of the magnetron type. Such a device includes a centrally disposed cathode structure H and an anode structure l2 spaced from and surrounding said cathode structure.

While not limited thereto, the cathode structure ll may comprise a cathode sleeve l3, made. for example, of nickel, and provided, adjacent its upper end, with a coating M of any preferred electron-emissive coating, such as a combination of the oxides of the alkaline-earth metals. The

upper, open end of the sleeve I3 is preferably closed by a shield l5, and said sleeve preferably carries, immediately below the lower extremity of the coating I 4, another shield l6. Mounted within the sleeve I3 is a heating coil ii, the upper end of said coil being electrically connected to said sleeve and the lower end thereof being electrically connected to a lead-in conductor ill. The latter passes downwardly out of the device through the sleeve l3 and. is supported in spaced relationship to said sleeve by insulating members l9 and 20. Heating current may be supplied to the coil I! by connecting the sleeve I3 and the lead-in conductor l8 to the terminals of any preferred voltage source, not shown. The manner of supporting the cathode structure H with respect to the anode structure l2 will be described at a later point in this specification.

The anode structure I2 preferably comprises a cylindrical envelope member 2|, made of conductive material, and having its open ends closed by annular, conductive supporting members 22 and 23. While not limited thereto, these supporting members, are, preferably, the spaced opposed pole pieces with which devices of the type to which the present invention relates are generally provided for supplying the conven tional longitudinal magnetic field in the interaction space between the cathode and anode structures of such devices.

The members 22 and 23 are provided with central Openings 24 and 25. Surrounding the opening 24, the member 22 is provided with a multiplicity of bores 26 having portions 21 of enlarged diameter, and surrounding the opening 25, the member 23 is provided with a multiplicity of bores 28 having portions '29 of enlarged diameter. The bores 26 are of somewhat greater diameter than the bores 28 for a purpose which will later become apparent, and the enlarged bore portions 21 and 29 constitute, as will be understood to those skilled in the art, radio-frequency chokes.

Carried by the supporting members 22 and 23 is a plurality of U-shaped, relatively short and relatively long, electron-receiving members 30 and 3|, these members being made of hollow, tubular, conductive material and including, respectively, yoke portions 32 and 33, and leg portions 34 and 35, and 36 and 31. The members 32 and 3!. have their leg portions 34 and 35, and 36 and 31, passing through the bores 26 of the supporting member 22, in spaced relationship to the walls thereof, and anchored in the bores 28 of the supporting member 23. The arrangement of the U-shaped members 30 and 3! is such that the shorter members alternate with the longer members, and the legs of each of such members are disposed, respectively, on opposite sides of registering predetermined diameters of the supporting member 22 and 2t. Adjacent the upper surface of the supporting member 22, all of the legs 36 to 3'5, inclusive, of all of the U-shaped members 3!] and 3! are securely connected to said supporting member 22 by inductive leads 3%, and the electrical length of the members and 3!, between said inductive leads 538 and the lower ends of the legs 3 3 to 31, inclusive, is a half wave of the operating wave-length of the device, whereby each pair of adjacent legs to ill, inclusive, together with those portions of the supporting members 22 and '23 lying therebetween, constitute a resonant transmission line, more particularly, a half wave line induc- Y tively closed at both ends.

The yokes 32 and .33 of the members fill and Bi extend above the supporting member 22 into a space es which is enclosed by a dome id made. preferably, of insulating material. The yolzes of the longer members iiiare electrically interconnected by conductive strap M whereby said longer members 3| jointly function as a single radiating element.

The purpose of making the members and of hollow, tubular material is to enable the circulation therethrough of a cooling iiuiol, thus enabling dissipation of anode heat. Th cooling fluid is supplied to and withdrawn from an annular header 42 provided with a partition see Fig. 3, disposed along a line lyi in the plane of the above referred to predetermined diameters of the supporting members 22 and the partition dividing the header into coolant-receiving and coolant-discharging chambers and A15. The header :32 is also provided with openings 2 registering with the bores of the supporting member The receiving chamber is provided with an inlet port and the discharging chamber is .rovided with an outlet port ii.

Thus, the legs 3d of the U-shape members and the legs 3Sof the ll-shaped members 3i communicate with the cooiant-receiving chamber 5-4 of the header 32, while the legs of the U" shaped members til and the legs 3? of the U- shaped members 3i communicate with the coolant-discharging chamber 35 or" the header ii.

In order to support the cathode structure ll with respect to the anode structure it, an inner Wall of the header 22 is made longer than the depth of said header, and secured to said wall is an insulating ferrule fastened at its other end to the cathode sleeve l3.

Substantially at the electrical centers of the resonant transmission lines defined by the legs 3 2- to inclusive, and the intervening portions of the supporting members and alternate legs are electrically interconnected by a modelocking conductive strap and the intervening legs are similarly electrically interconnected by a mode-locking conductive strap bl.

When the cathode of a device such as has been described is provided with appropriate heating current, and a suitable potential difference is established between said cathode and anode, and a cooling fluid is circulated through the electronreceiving members of said anode, the device gener'atesappreciable radio-frequency power under continuous-wave operating conditions without overheating.

This completes the description of the aforesaid illustrative embodiment of the present invention. It will be noted from all of the foregoing that the device not only functions to generate appreciable power under continuous-wave operating conditions, but it is simple in its design, is easy and economical to fabricate and assemble, and is of such construction as to permit its being built with relatively small dimensions.

Other objects and advantages of the present invention will readily occur to those skilled in the art to which the same relates.

What is claimed is:

1. An electron-discharge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member; a pair of supporting members connected to said envelope member; a header having coolant-receiving and coolant-discharging chambers, and inlet and outlet ports communicating, respectively, with said chambers; and a plurality of hollow electron-receiving members carried by said supporting members and communicating at opposite ends, respectively, with said coolant-receiving and coolant-discharging chambers.

2. An electronedischarge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member; a pair of spaced, opposed, electrically-conductive pole pieces connected to said envelope member; a header having coolant-receiving and coolant-discharging chambers, and inlet and outlet ports communicating, respoctively, with said chambers; and a plurality of hollow electron-receiving members caried by said pole pieces and communicating at opposite ends, respectively, with said coolant-receiving and coolant-dischar ing chambers.

3. An electron-discharge device comprising; a cathode; and an anodestructure spaced from said cathode; said anode structure including an envelope member; a pair of supporting members connected to said envelope member; a header having coolant-receiving and coolant-discharging chambers, and inlet and outlet ports communicating, respectively, with said chambers; and a plurality of hollow, tubular, U-shaped members carried by said supporting members and communieating at opposite ends, respectively, with said coolant-receiving and coolant-discharging chambers; each pair of adjacent legs of said U-shaped members, together with those portions of said supporting members lying therebetween, constituting a resonant transmission line.

4. An electron-discharge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member, a pair of spaced, opposed, electrically-conductive pole pieces connected to said envelope member; a header having coolantreceiving and coolant-discharging chambers, and inlet and outlet ports communicating, respectively, with said chambers; and a plurality of hollow, tubular, U-shaped members carried by said pole pieces and communicating at opposite ends, respectively, with said coolant-receiving an coolant-discharging chambers; each pair or ad acent legs of said U-shaped members, together with those portions of said pole pieces lyin therebetween, constituting a resonant transmission line.

5. An electron-discharge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member; a pair of supporting members connected to said envelope member; a header having coolant-receiving and coolant-discharging chambers, and inlet and outlet ports communicating, respectively, with said chambers; a plurality of hollow electron-receiving members carried by said supporting members and communicating at opposite ends, respectively, with said coolant-receiving and c001ant-discharging chambers; and a pair of conductive straps electrically connected, respectively, to alternate and intervening electron-receiving members,

6. An electron-discharge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member; a pair of spaced, opposed, electrically-conductive pole pieces connected to said envelope member; a header having coolantreceiving and coolant-discharging chambers, and inlet and outlet ports communicating, respectively, with said chambers; a plurality of hollow electron-receiving members carried by said pole pieces and communicating at opposite ends, respectively, With said coolant-receiving and cool-- ant-discharging chambers; and a pair of conductive straps electrically connected, respectively, to alternate and intervening electron-receiving members.

7. An electron-discharge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member; a pair of supporting members connected to said envelope member; a header having coolant-receiving and coolant-discharging chambers, and inlet and outlet ports communicating, respectively, with said chambers; a plurality of hollow, tubular, U--shaped members carried by said supporting members and communicating at opposite ends, respectively, with said coolant-receiving and coolant-discharging chambers; each pair of adjacent legs of said U- shaped members, together with those portions of said supporting members lying therebetween, constituting a resonant transmission line; a conductive strap electrically connected to both legs of all alternate electron-receiving members; and a second conductive strap electrically connected to both legs of all intervening electron-receiving members.

8. An electron-discharge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member; a pair of spaced, opposed, electrically-conductive pole pieces connected to said envelope member; a header having coolantreceiving and coolant-discharging chambers, and inlet and outlet ports communicating, respectively, with said chambers; a plurality of hollow, tubular, U-shaped members carried by said pole pieces and communicating at opposite ends, respectively, with said coolant-receiving and coolantdischarging chambers; each pair of adjacent legs of said U-shaped members, together with those portions of said pole pieces lying therebetween, constituting a resonant transmission line; a conductive strap electrically connected to both legs of all alternate U-shaped members; and a second conductive strap electrically connected to both legs of all intervening U-shaped members.

9. An electron-discharge device comprising: a cathode; and an anode structure spaced from said cathode; said anode structure including an envelope member; a pair of supporting members connected to said envelope member; a header having coolant-receiving and coolant-discharging chambers, and inlet and outlet ports coinmunicating, respectively, with said chambers; and a plurality of hollow, U-shaped electronreceiving members carried by said supporting members and having their legs communicating, respectively, with said coolant-receiving and coolant-discharging chambers; all of the legs of said U-shaped members lying in the surface of a cylinder and each pair of adjacent legs of said U-shaped members, together with those portions of said supporting members lying therebetween, constituting a resonant transmission line.

WILLIAM C. BROWN.

REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,189,501 Helbig Feb. 6, 1940 2,451,987 Sloan Oct. 19, 1948 2,455,952 Schmidt Dec. 14, 1948 2,462,698 Wilbur Feb. 22, 1949 

